According to the National Tropical Botanical Garden
website, the seeds of the breadnut are low in fat (6-29%) and high in protein (13-20%) compared to seeds such as the almond and are a good source of minerals.
All I know is that they are delicious if properly prepared, with a flavour and texture very much like that of chestnuts. Breadnut, although originally from New Guinea and Indonesia, is not common in Oceania like the breadfruit but has spread across the Caribbean, so you might find it there. If so you have stumbled across a versatile seed that can be treated exactly as chestnuts would be. In the photo above you can see the seeds embedded in the breadnut's ripe flesh, below are the seeds themselves.